Dissertation > Excellent graduate degree dissertation topics show

Research on the Surface REconstruction Based on Geometric Shapes

Author: NiMinMin
Tutor: HeXueMing
School: Jiangnan University
Course: Mechanical Design and Theory
Keywords: topology reconstruction convex hull Delaunay triangulation αa-shape γ-shape
CLC: TP391.7
Type: Master's thesis
Year: 2010
Downloads: 61
Quote: 0
Read: Download Dissertation

Abstract


While free-form surface reconstruction is an important technology in reverse engineering which can realize digital duplication and improvements, it has a wide prospect. Usually, surface reconstruction adopts the basic mode of point、curve、surface but it is complicated. Another method is on the basis of triangle meshes segmentation with the disadvantage of little precision. Then direct surface reconstruction using geometric shapes by triangle meshes is arised, and it can avoid the point segmentation and curves fitting.In order to get a large number of point data and improve the measurement speed, normally non-contact measurement is used, such as a laser scanner. First, this paper studys the theories, methods and the characteristic of existing measurement machines.By numbers of models measurement, the research is based on the point cloud acquired by TDV800 laser scanner in this paper. Pre-processing which includes format conversion, data merge, noise filter, coordinate transformation and data reduction is observed and proved by physical models, mainly to offer points data with reliable quality.In the process of geomatric shape construction, two basal but important problems are researched such as convex hull and Delaunay triangulation which are used to subdivide a point set. This paper presents region segmentation by four maxima and minima points, which are saved in the link list of convex hull vertex. Meanwhile, these points divide other points into two areas, only to consider the outer points since the inner points mustn’t be convex hull vertexes. The new areas are subdivided untill all the areas are NULL by the farthest distance method, in which we can get all the convex hull vertexes and save them in the link list. These points are sorted and connected by anticlockwise vector angles. Meanwhile, it can judge those non convex hull vertexes. According to the property of maximum the minimum angle and four points of a circle presented in this paper, the topology annexation is constructed with point by point scanning, which accomplishes the Delaunay triangulation construction.The paper adopts surface reconstruction by a shape. First, triangle mesh is stored and called by STL. The simplexes are classified and computed in order to obtain a interval by the cicumsphere radius and centre of every simplex. Data structure is designed to save them. Through self-selection, a-shape can be reconstructed by different a parameters.α-shape avoids cockamamie calculations and accelerates the speed. The paper usesγshape in consideration of non-uniform samples by modulating the global factor a with a local scale factor, which is called y. This paper determines the value of gamma by using the distance from a point to its negative pole. To solve holes and bridges, the minimaγof its every vertex is identified as the local scale factor for a simplex, which is used to reconstruct a surface.Fouse on the research contents, a visual software of surface reconstruction based on gemetric shapes is designed by using VC++ programming and OpenGL graphics. The interface design and operation of this software are demonstrated by existing point cloud samples, which realizes the theory in this paper. The data provided by the Stanford 3D Scanning Repository is reconstructed, such as Dragon, Happy Buddha, Stanford Bunny.

Related Dissertations

  1. OSG-based three-dimensional irregular terrain matching military standard applied research,E919
  2. Research of Digital Elevation Model Generation and Visualization Based on TIN,TP391.41
  3. The Mechanism Research of Visualization Experiment Approach for Solving System Global Shortest Path,TP13
  4. Key Technology Research of Block Modeling in Seismic Imaging System,TP391.41
  5. System design and application of a two-dimensional grid Automeshening,TP391.41
  6. Texture Based Fractal Imagery Modeling, Rendering and Morphing Algorithm,TP391.41
  7. The Primary Research for Flow Simulation on Unstructured Grids,O35
  8. The Research on Carving Surface Modeling Based on Planar Random Closed Graph,TP391.72
  9. Research on One-Class Classifier Based on Geometric Covering Model of Target Class in High-Dimensional Space,TP391.41
  10. Study on Improved Fingerprint Identification Algorithm Based on Delaunay Triangulation,TP391.41
  11. An Improvement and Exploration for Digital Signature Technology Based on Convex Hull Theory and Information Hiding,TN918.2
  12. Design and Implementation of Doppler Weather Radar Data Analysis System,TN959.4
  13. Delaunay Triangulation Parallel Construction Method and Its Application in Map Generalization,P283
  14. Adjusted Empirical Euclidean Likelihood and Its Properties,O212.7
  15. Reseach on Semi-Supervised Clustering Algorithm Based Convex Hull,TP181
  16. Research and Application of Imbalance Data Classification Based on Support Vector Machine,TP274
  17. The extracted key technology of the three-dimensional visualization of isosurface,TP391.41
  18. Research on a Sparse Stereo Matching Algorithm Based on Belief Propagation,TP391.41
  19. The Investigation of 3D Scene Reconstruction Algorithm Based on Laser Scan Data,TP391.41
  20. Delaunay Triangulation Method in Three-dimensional Terrain Visualization Application,TP391.41

CLC: > Industrial Technology > Automation technology,computer technology > Computing technology,computer technology > Computer applications > Information processing (information processing) > Machine-assisted technology
© 2012 www.DissertationTopic.Net  Mobile